EVP_CHACHA20

Section: OpenSSL (3)
Updated: 2020-07-28
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NAME

EVP_chacha20, EVP_chacha20_poly1305 - EVP ChaCha20 stream cipher

SYNOPSIS

 #include <openssl/evp.h>

 const EVP_CIPHER *EVP_chacha20(void)
 const EVP_CIPHER *EVP_chacha20_poly1305(void)

DESCRIPTION

The ChaCha20 stream cipher for EVP.

EVP_chacha20()

The ChaCha20 stream cipher. The key length is 256 bits, the IV is 128 bits long. The first 32 bits consists of a counter in little-endian order followed by a 96 bit nonce. For example a nonce of:

000000000000000000000002

With an initial counter of 42 (2a in hex) would be expressed as:

2a000000000000000000000000000002

EVP_chacha20_poly1305()

Authenticated encryption with ChaCha20-Poly1305. Like EVP_chacha20(), the key is 256 bits and the IV is 96 bits. This supports additional authenticated data (AAD) and produces a 128-bit authentication tag. See the ``AEAD Interface'' in EVP_EncryptInit(3) section for more information.

RETURN VALUES

These functions return an EVP_CIPHER structure that contains the implementation of the symmetric cipher. See EVP_CIPHER_meth_new(3) for details of the EVP_CIPHER structure.

COPYRIGHT

Licensed under the OpenSSL license (the ``License''). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.